Paper and its production



Patented Dec. 28, 1943 PAPER AND ITS PRODUCTION Otto Hansen, Mannheim,mann, Ludwigsha'fen-on heim, Germany, assi ments, to General Ani NewYork, N. Y.,

gnors,

line & Film Corporation, a corporation of Delaware and Hans Scheuer--the Rhine Oggersby mesne assign- No Drawing. Application August 22,1939, Serial No. 291,330. In Germany'August 25, 1938 I 6 Claims.

The present invention consists in a process for improving paper andpaper obtainable according to this process. y

We have found that the compounds which are soluble or capable ofswelling in water obtainable by the action of 'monohalogenacetic acidsubstances, i. e. monohalogenacetic acids or their salts, on woodpretreated with an alkali metal hydroxide are excellent assistants orimproving agents for the preparation or finishing of paper. By treatingthe paper during its preparation or finishing with the said substances,paper with excellent properties is obtained. Such substances may beprepared for example according to the application Ser. No. 244,418,filed in the names of Michael Jahrstorfer and Julius Beck on December'7, 1938, now Patent No. 2,294,666, granted on September 1, 1942,preferably by means of monochloracetic acid or its alkali salts. Thesaid substances are usually employed in the form of their water-solublealkali salts.

These compounds, hereinafter referred to as wood ethers, may be used forexample as addian aqueous solution of the alkali salts of the woodethers and the web thus treated then being treated with a solution of ametal compound having a precipitant action, for example with analuminium or titanium salt or an aluminium oxide sol solution, theinsoluble salt of the wood ether thus being formed on the paper. Paperprepared in this way is distinguished by a high tensile strength, abetter handle and a very good wet strength.

According to this invention it is possible to use in the improvement orfinishing of paper products which cheap raw materials. Contrary toexpectation the paper, cardboard, pasteboard and like products preparedwith their aid are distinguished by a satisfactory fastness to light,which is the more surprising since ordinary wood is used as initialtions in the resin sizing of paper in pulp, The V amount of Wood etheradded may be for example from 0.5 to 3 per cent or more with referenceto the amount of air-dried fiber. By further working up there isobtained a paper which differs from papers prepared by the usual resinsizing methods in that it has a higher folding value, better tensilestrength and generally higher mechanical strength,

The Wood ethers may also be used instead of the usual casein sizing(coating of the paper), for example by applying to the paper web afterleaving the paper machine, for example in a brush coating machine,solutions of the alkali salts of wood ethers, if desired with anaddition of the usual p gments.

In sizing in pulp or coating of the paper a precipitation orinsolubilization of the wood ethers may be effected by anaftertreatment, as for example with aluminium or titanium salts. Thismay be effected with aluminium sulphate solutions or also with solutionsof colloidal watersoluble aluminium oxide or also with titanium saltsolutions. The treatment with the said metal compounds may also becarried out in the presence of protective colloids.

The aqueous solutions of the wood ethers are also suitable for theapplication of pigment suspensions to the paper web during itsformation, as for example in the manner described in the German Patent661,652. By aftertreating this infusion with aluminium or titaniumcompounds, the Wet strength of the paper maybe further in-' creased.

The wood ethers may also serve advantageously for the improvement ofpaper by the immersion process, the finished paper being introduced intomaterial for the wood ethers.

The following examples will further illustrate how the said inventionmay be carried outin practice but the invention is not restrictedtothese examples,

Example 1 To a paper pulp of per cent of bleached sulphite cellulose and20 per cent of bleached straw cellulose in a hollander there is added 1per cent of saponified resin size saponified to a degree of 80 per centand employed in the form of a 50 per cent solution (with reference tothe dry fiber substance). There is then added from about 0.6 to 1 percent of the sodium salt of the wood ether prepared according to Example1 j of the said application Ser. No. 244,418. The pulp is worked well inthe hollander and after about 20 minutes 2 per cent of aluminiumsulphate in solid or dissolved formare added. A valuable writing papermay be prepared from the pulp thus treated on the known paper machines.

Example 2 Eaiample 3 0.5 per cent of colophony in the form of its sodiumsoap is added to a paper pulp in a hollander. 3 percent of the sodiumsalt of the wood ether described in the foregoing examples are thenadded and, after thorough working, 4 per cent of aluminium sulphate. Thepaper pulp is worked up into paper in the usual manner, a product withexcellent strength properties thus being obtained.

are very readily accessible from very E'zaniple4.-

1000 parts ofa titanium white-pigment con-' sisting of 90 per cent oftitanium dioxide and 10 per cent of barium sulphate are kneaded with4000 parts of blanc fixe and 2501pa1'tsfof talc' with the elder water.Into the resulting paste there are stirred 'lo .parts of a mixtureconsisting of montanic'acid and its sodium salt' and from 250 to 400parts of the sodiumsalt of a.

wood ether previously dissolved in water. I

The mass thus obtained is adjusted to the viscosity necessary forapplication by the addition of water and applied in the usual way in a,brush coating machine to a paper web. The paper web thus coated istreated before or after drying with an aqueous aluminium sulphatesolution containing about 10 grams of aluminium sulphate per liter forexample by leading the paper web ac-. cording to the immersion processthrough the aluminium sulphate solution or spraying the latter onto thecoated paper web through nozzles.

Example 5 2.5 kilograms of titahiumwhite pigment, consisting of about9'0 per-cent of titanium dioxide and 10 per cent of varium sulphate, aremade into a paste with 12 liters of water in a Ienart mixer. The aqueoussuspension is th env introduced with rapid mixing into 140 liters of anaqueous starch solution containing 800 grams of potato-meal made into apaste. While stirring there are added to the mixture an aqueous solutionof 120 grams of the sodium salt of a wood ether in 45 liters of water.

The suspension of titanium white thus prepared and stirred'is applied tothe paperweb on the long sieve between the first and second suctionportions. The water is thus sucked through the paperand passes belowthepaper web into the suction .devices while the pigment with the. greaterpart of the sodium salt of the wood etherand starch is retained by theswollen paper texture. The pigment is thus firmly cemented with thepaper.-

A paper preparedin this way is eminently suitable-for printing and mayserve as a substitute for coated paper.

If, under the above mentioned conditions, instead of 1.6 kilograms oftitanium white pigment, there be used 2.2 kilograms of lithopone with acontent of 60 per cent of zinc sulphide and 9.

- corresponding amount of blanc fixe, equally good coatings on paper areobtained.

- On the surface of the paper thus treated theremay be sprayed ifdesired before drying an about.

1 per cent solution of an aluminium oxide sol with the aid of a sprayingdevice, the wood ether thus being converted into the insoluble aluminiumsalt. The paper thus prepared has good wet strength and is eminentlysuitable for printing.

Example 6 A finished paper web, after leaving the paper machine, is ledthrough a 2 per cent aqueous that the wood ether is converted into itsaluminiumsalt. The, paper thus obtained has a specially high tensilestrength, a great folding value and avery good weti strength. Itgistherefore be" carried out in a single bath process withthe suitable forexample for the preparation of waterproof bags.

The conversion into the aluminium salt may aid' of-protective colloids,as for example animal glue or-gum arabic.

What we claim is:

1. Paper of improved fastness to light, high folding value andw'et'strength which contains in the sizing aproduct obtainable by theaction of a member selected from the group'consisting of a monohalogenacetic acid and a water soluble salt thereof on wood pre-treated withanalkali hydroxide and from which substantially no constituents have beenremoved by this pre-treatment.

2. A paper article as defined in claim 1 in which the said product is inthe form of an alkali metal salt.

3. In the process for producing'paper products of improved fastness tolight, high folding .value and wet strength, the step which comprisesadding to the sizing of the paper material in the pulp a productobtainable by the action of a member selected from the groupconsisting'of a monohalogen acetic acid and a water soluble salt thereofon wood pre-treated with an alkali hydroxide and from whichsubstantially no constituents have been removed by this pro-treatment.

4. Paper of-improved fastness to 'light, high folding value and wetstrength which contains the reaction product, of an aluminumioxide solon the product obtainable by the action of a member selected from thegroup consisting of a monohalogen acetic acid and a water soluble saltthereof on wood pretreated with an alkali hydroxide and from whichsubstantially no constituents have been removed by'this pre-treat ment.

5. In'the process for producing paper products of 'improved fastnesstolight, high folding value and wet strength, the step which comprisesadding to the sizing of the paper material in the pulp, a productobtainable by the action of a monochloroacetic acid alkali metal salt onwood pre-treated with an alkali hydroxide and from which substantiallyno constituentshave been removed by this pr'e-treatment.

6. A process for producing paper of high wet and tensilestrength,-folding value and fast'ness to light which comprisesimpregnating the paper with a product, in the form of its alkali'metalsalt, obtainable by the action of a member selected from the groupconsisting f a monohalogen' acetic acid' and a water soluble saltthereof on wood pre-treated 'with an alkali hy-;

droxide'and from which substantially no constituents have been removedby this pre-treat-

